The present invention refers to a device for cooling a bearing of a centrifugal separator, comprising a portion adjacent to the bearing and at least one channel, which extends through this portion, is arranged to receive a flow of a cooling medium and comprises at least two successive channel portions and at least one connecting portion provided between successive channel portions. Moreover, the invention refers to a method of cooling a bearing of a centrifugal separator, wherein a cooling medium is conveyed in a flow through at least one channel, which is provided in a portion adjacent to the bearing and comprises at least two channel portions successively provided.
The cooling of bearings of centrifugal separators has traditionally involved an internally recirculating air stream absorbing the heat in the actual bearing and giving off the heat to other parts of the centrifugal separator, for instance the inner side of the wall of the support of the centrifugal separator. Such a system requires the provision of a fan forcing the air stream through the bearings. However, such a fan requires space and therefore it may be difficult to provide the fan in the proximity of the bearing. Furthermore, the fan proper generates additional heat which has to be cooled away. In addition, the fan causes a significant complexity with respect to the sealing against other spaces of the centrifugal separator and against the environment, which in many cases may give rise to problems.
One way of solving at least a part of these problems is to provide a separate cooling of the bearing, i.e. to cool the bearing by means of a fluid carried through a cooling channel separated from the bearing proper. In such a manner, the cooling fluid need not be mixed with other fluids in the centrifugal separator. However, by such a cooling system it is difficult to obtain a sufficient cooling capacity since the space available for the provision of separate cooling channels in the proximity of the bearing is limited.
GB-A-2 121 118 discloses a device for cooling a slide bearing, comprising a portion adjacent to the slide bearing and a channel extending through this portion and being arranged to receive a flow of a cooling medium. The channel comprises successive helical channel portions and a connecting portion provided between successive channel portions. The connecting portion is designed in such a manner that the flow is redirected about 180.degree.. In this document nothing is said about the appearance of the flow or the influence of the redirection of the flow. Instead, the connecting portions rather appear to be designed in such a manner that their influence on the flow is as small as possible.
GB-A-985 804 discloses a device for cooling a roller bearing, comprising a portion which encloses the roller bearing and which comprises a plurality of parallel radial flanges extending in the peripheral direction. The channel comprises an axial inlet passage, an axial outlet passage and a plurality of parallel channel portions defined by said flanges. From the inlet passage the flow is redirected 90.degree. into the different channel portions. It is also mentioned that it is possible to provide the flanges in an overlapping configuration in such a manner that the channel portions will extend at least partly in series with each other. However, also this document is silent about the appearance of the flow or the influence of the redirection of the flow.